Quanta LG9 motherboard schematic set, board number DA0LG9MB6E0 at revision 1A, in a 2.03 MB RAR. The name gives no retail brand or model, so match by the DA0LG9MB6E0 string printed on the PCB, which follows Quanta's DA0-plus-project numbering. The document supports fault-finding on power rails, enable and power-good signals, USB and display paths, and helps identify the parts in a shorted circuit. Confirm the revision on the board is 1A, since other revisions of the same project can use different components.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @IT_SERVICE_WORLD. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.